Coupling



FIG. 1 is a perspective view of a coupling.

FIG. 2 is a front view of the coupling of FIG. 1.

FIG. 3 is a back view of the coupling of FIG. 1.

FIG. 4 is a right side view of the coupling of FIG. 1.

FIG. 5 is a left side view of the coupling of FIG. 1.

FIG. 6 is a top view of the coupling of FIG. 1; and,

FIG. 7 is a bottom view of the coupling of FIG. 1.

The broken lines shown illustrate the portions of the coupling that form no part of the claimed design. 

CLAIM The ornamental design for a coupling, substantially as shown and described. 